• Nutrition Research and Practice
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• 제16권1호
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• pp.46-59
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• 2022

BACKGROUND/OBJECTIVES: Aster yomena (Kitam.) Honda (AY) has remarkable bioactivities, such as antioxidant, anti-inflammation, and anti-cancer activities. On the other hand, the effects of AY against obesity-induced insulin resistance have not been reported. Therefore, this study examined the potential of AY against obesity-associated insulin resistance in high-fat diet (HFD)-fed mice. MATERIALS/METHODS: An obesity model was established by feeding C57BL/6J mice a 60% HFD for 16 weeks. The C57BL6/When ethyl acetate fraction from AY (EFAY) at doses of 100 and 200 mg/kg/day was administered orally to mice fed a HFD for the last 4 weeks. Normal and control groups were administered water orally. The body weight and fasting blood glucose were measured every week. Dietary intake was measured every other day. After dissection, blood and tissues were collected from the mice. RESULTS: The administration of EFAY reduced body and organ weights significantly compared to HFD-fed control mice. The EFAY-administered groups also improved the serum lipid profile by decreasing the triglyceride, total cholesterol, and low-density lipoprotein compared to the control group. In addition, EFAY ameliorated the insulin resistance-related metabolic dysfunctions, including the fasting blood glucose and serum insulin level, compared to the HFD-fed control mice. The EFAY inhibited lipid synthesis and insulin resistance by down-regulation of hepatic fatty acid synthase and up-regulation of the AMP-activated protein kinase pathway. EFAY also reduced lipid peroxidation in the liver, indicating that EFAY protected hepatic injury induced by obesity. CONCLUSIONS: These results suggest that EFAY improved obesity-associated insulin resistance by regulating the lipid and glucose metabolism, suggesting that AY could be used as a functional food to prevent obesity and insulin resistance.

• Preventive Nutrition and Food Science
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• 제20권2호
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• pp.94-101
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• 2015

Grape products have been known to exert greater antioxidant and anti-obesity than anti-hyperglycemic effects in animals and humans. Omija is used as an ingredient in traditional medicine, and it is known to have an anti-hyperglycemic effect. We investigated whether the combined extracts of grape pomace and omija fruit (GE+OE) could reduce fat accumulation in adipose and hepatic tissues and provide beneficial effects against hyperglycemia and insulin resistance in type 2 diabetic mice. C57BL/KsJ-db/db mice were fed either a normal control diet or GE+OE (0.5% grape pomace extract and 0.05% omija fruit extract, w/w) for 7 weeks. GE+OE decreased plasma leptin and resistin levels while increasing adiponectin levels and reducing the total white adipose tissue weight. Furthermore, GE+OE lowered plasma free fatty acid (FFA), triglyceride, and total-cholesterol levels as well as hepatic FFA and cholesterol levels. Hepatic fatty acid synthase and glucose 6-phosphate dehydrogenase activities were decreased in the GE+OE group, whereas hepatic ${\beta}$-oxidation activity was increased. Furthermore, GE+OE supplementation not only reduced hyperglycemia and pancreatic ${\beta}$-cell failure but also lowered blood glycosylated hemoglobin and plasma insulin levels. The homeostasis model assessment of insulin resistance levels was also decreased and the decrease seems to be mediated by the lowered activities of hepatic glucose-6-phosphatase and phosphoenolpyruvate carboxykinases. The present data suggest that GE+OE may have the potential to reduce hyperglycemia, insulin resistance, and obesity in patients with type 2 diabetes.

• Biomolecules & Therapeutics
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• 제29권4호
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• pp.419-426
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• 2021

In this study, we aimed to investigate the effects of 8 weeks of treatment with a combination of evogliptin and leucine, a branched-chain amino acid, in mice with high-fat diet (HFD)-induced diabetes. Treatment with evogliptin alone or in combination with leucine reduced the body weight of the mice, compared to the case for those from the HFD control group. Long-term treatment with evogliptin alone or in combination with leucine resulted in a significant reduction in glucose intolerance; however, leucine alone did not affect postprandial glucose control, compared to the case for the mice from the HFD control group. Furthermore, the combination of evogliptin and leucine prevented HFD-induced insulin resistance, which was associated with improved homeostasis model assessment for insulin resistance, accompanied by markedly reduced liver fat deposition, hepatic triglyceride content, and plasma alanine aminotransferase levels. The combination of evogliptin and leucine increased the gene expression levels of hepatic peroxisome proliferator-activated receptor alpha, whereas those of the sterol regulatory element-binding protein 1 and stearoyl-CoA desaturase 1 were not altered, compared to the case in the HFD-fed mice (p<0.05). Thus, our results suggest that the combination of evogliptin and leucine may be beneficial for treating patients with type 2 diabetes and hepatic steatosis; however, further studies are needed to delineate the molecular mechanisms underlying the action of this combination.

• Archives of Pharmacal Research
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• 제29권9호
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• pp.768-776
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• 2006

Non-alcoholic fatty liver disease (NAFLD) is common in obesity. However, weight reduction alone does not prevent the progression of NAFLD to end-stage disease associated with the development of cirrhosis and liver disease. In a previous experiment, 50% ethanol extract of Acanthopanax senticosus stem bark (ASSB) was found to reduce body weight and insulin resistance in high fat diet-induced hyperglycemic and hyperlipidemic ICR mice. To evaluate the anti-steatosis action of ASSB, insulin-resistant ob/ob mice with fatty livers were treated with ASSB ethanol extract for an 8 week-period. ASSB ethanol extract reversed the hepatomegaly, as evident in reduction of % liver weight/body weight ratio. ASSB ethanol extract also specifically lowered circulating glucose and lipids, and enhanced insulin action in the liver. These changes culminated in inhibition of triglyceride synthesis in non-adipose tissues including liver and skeletal muscle. Gene expression studies confirmed reductions in glucose 6-phosphatase and lipogenic enzymes in the liver. These results demonstrate that ASSB ethanol extract is an effective treatment for insulin resistance and hepatic steatosis in ob/ob mice by decreasing hepatic lipid synthesis.

• Nutrition Research and Practice
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• 제10권5호
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• pp.507-515
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• 2016

BACKGROUND/OBJECTIVES: This study was designed to investigate whether Gynura procumbens extract (GPE) can improve insulin sensitivity and suppress hepatic glucose production in an animal model of type 2 diabetes. MATERIALS/METHODS: C57BL/Ksj-db/db mice were divided into 3 groups, a regular diet (control), GPE, and rosiglitazone groups (0.005 g/100 g diet) and fed for 6 weeks. RESULTS: Mice supplemented with GPE showed significantly lower blood levels of glucose and glycosylated hemoglobin than diabetic control mice. Glucose and insulin tolerance test also showed the positive effect of GPE on increasing insulin sensitivity. The homeostatic index of insulin resistance was significantly lower in mice supplemented with GPE than in the diabetic control mice. In the skeletal muscle, the expression of phosphorylated AMP-activated protein kinase, pAkt substrate of 160 kDa, and PM-glucose transporter type 4 increased in mice supplemented with GPE when compared to that of the diabetic control mice. GPE also decreased the expression of glucose-6-phosphatase and phosphoenolpyruvate carboxykinase in the liver. CONCLUSIONS: These findings demonstrate that GPE might improve insulin sensitivity and inhibit gluconeogenesis in the liver.

• Journal of Ginseng Research
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• 제44권2호
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• pp.238-246
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• 2020

Background: Dietary fat has been suggested to be the cause of various health issues. Obesity, hypertension, cardiovascular disease, diabetes, dyslipidemia, and kidney disease are known to be associated with a high-fat diet (HFD). Obesity and associated conditions, such as type 2 diabetes mellitus and nonalcoholic fatty liver disease (NAFLD), are currently a worldwide health problem. Few prospective pharmaceutical therapies that directly target NAFLD are available at present. A Traditional Chinese Medicine, ginseng-plus-Bai-Hu-Tang (GBHT), is widely used by diabetic patients to control glucose level or thirst. However, whether it has therapeutic effects on fat-induced hepatic steatosis and metabolic syndrome remains unclear. Methods: This study was conducted to examine the therapeutic effect of GBHT on fat-induced obesity, hepatic steatosis, and insulin resistance in mice. Results: GBHT protected mice against HFD-induced body weight gain, hyperlipidemia, and hyperglycemia compared with mice that were not treated. GBHT inhibited the expansion of adipose tissue and adipocyte hypertrophy. No ectopic fat deposition was found in the livers of HFD mice treated with GBHT. In addition, glucose intolerance and insulin sensitivity in HFD mice was also improved by GBHT. Conclusion: GBHT prevents changes in lipid and carbohydrate metabolism in a HFD mouse model. Our findings provide evidence for the traditional use of GBHT as therapy for the management of metabolic syndrome.

• BMB Reports
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• 제49권3호
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• pp.139-148
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• 2016

In the past decade, the incidence of type 2 diabetes (T2D) has rapidly increased, along with the associated cardiovascular complications. Therefore, understanding the pathophysiology underlying T2D, the associated complications and the impact of therapeutics on the T2D development has critical importance for current and future therapeutics. The prevailing feature of T2D is hyperglycemia due to excessive hepatic glucose production, insulin resistance, and insufficient secretion of insulin by the pancreas. These contribute to increased fatty acid influx into the liver and muscle causing accumulation of lipid metabolites. These lipid metabolites cause dyslipidemia and non-alcoholic fatty liver disease, which ultimately contributes to the increased cardiovascular risk in T2D. Therefore, understanding the mechanisms of hepatic insulin resistance and the specific role of liver lipids is critical in selecting and designing the most effective therapeutics for T2D and the associated co-morbidities, including dyslipidemia and cardiovascular disease. Herein, we review the effects and molecular mechanisms of conventional anti-hyperglycemic and lipid-lowering drugs on glucose and lipid metabolism.

• 한국식품영양과학회지
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• 제44권2호
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• pp.173-181
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• 2015

본 연구는 scopoletin 식이 보충이 알코올로 인해 유발되는 인슐린저항성과 항산화방어계에 미치는 영향을 구명하고자 하였다. 실험동물은 4주령의 수컷 SD계 흰쥐에게 총 열량의 36%에 해당하는 알코올을 액체식이 형태로 8주간 공급하였으며, scopoletin은 알코올 액체식이 리터당 0.01 g과 0.05 g 두 수준으로 첨가하였다. 정상군은 알코올대조군과 동량의 에너지를 섭취하도록 하였다. 8주간의 알코올 급여는 공복 시 혈당 변화를 일으키지 않았으나 혈청 인슐린 함량을 증가시켰으며, 이는 인슐린저항성과 내당능 장애를 유발하였다. 그러나 scopoletin 저농도와 고농도 급여군 모두 인슐린 함량, 인슐린저항성 지표 및 내당능을 효과적으로 개선하는 것으로 나타났다. 알코올대조군은 p-PI3K의 단백질 발현을 유의적으로 낮추어 glucokinase 유전자 발현과 활성을 억제한 반면, 당신생 효소인 glucose-6-phosphatase의 유전자 발현과 활성을 유의적으로 높였다. 그러나 scopoletin 급여에 의하여 이들 변화는 완화되었다. 다른 당신생 효소인 phosphoenolpyruvate carboxykinase의 유전자 발현과 활성에는 영향을 미치지 않았다. 또한 scopoletin 급여군 모두 간조직의 aldehyde dehydrogenase의 활성은 알코올 대조군에 비해 증가된 반면, cytochrome P450 2E1 활성은 억제되었다. 또한 알코올로 인하여 낮아진 간조직 중의 항산화 효소(superoxide dismutase, catalase와 glutathione peroxidase)의 유전자 발현과 활성을 높임으로써 과산화수소 및 지질과산화물의 함량을 낮추었다. 이와 같이 0.001%의 scopoletin 급여량에서도 당대사의 유전자 변화를 통하여 만성 알코올로 유도되는 인슐린저항성을 개선하였으며, 알코올대사계 활성 및 항산화방어계 효소의 유전자 발현을 증가함으로써 알코올로 인한 과산화수소와 지질과산화물 생성을 개선하는 것으로 나타났다.

• Journal of Nutrition and Health
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• 제25권2호
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• pp.109-115
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• 1992

This study was undertaken to determine the effect of dietary fat to carbohydrate ratio on plasma glucose. free fatty acid level and hepatic glucokinase activity in normal or insulin treated diabetic rats. Sprague-Dawley male rats were fed with 3 different but isocaloric diets for 5 weeks. Diet 1 made to have low fat(4% corn oil and 65.8% corn starch wt/wt) : diet 2 medium fat (12% : 47.8%) : diet 3 high fat (20% : 29.8%) In the normal rats an apparent increase of GK activity was observed from the animal fed low fat diet when compared with other groups. GK activities were decreased in all the alloxan-diabetic rats than the normal rats. When insulin was injected the GK activities in all the livers of alloxan-diabetic rats restored to normal level and GK activity was highest in low fat group. In the entire group significant relationships were seen between the plasma glucose and GK activities(r=-0.6, p<0.001) FFA levels and GK activities(r=-0.63 p<0.001) Both in normal and insulin treated diabetic rats significantly depressed level of hepatic GK activity was observed in the livers of animals fed high fat diet for 5 weeks and depressed level of GK activity may be related to insulin resistance.

• Journal of Yeungnam Medical Science
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• 제12권2호
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• pp.269-281
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• 1995

포도당 중합체 투여로 유도한 고혈당 및 고인슐린 혈증이 인슐린 저항성의 발생에 미치는 영향을 규명하기 위하여 hyperinsulinemic euglycemic clamp 기법으로 측정한 당제거율, 당주입율 및 간의 당생성율과 방사성동위원소를 이용한 골격근의 당원질합성능을 측정한 본 연구결과를 요약하면 다음과 같다. Hyperinsulinemic euglycemic clamp 기법으로 평형상태에서 측정한 당제거율은 포도당 중합체군에서 혈중 인슐린의 생리적 및 최대농도 모두에서 정상대조군에 비해서 감소하였으며(p<0.05) STZ 당뇨군에서도 최대인슐린 농도에서 감소하였다(p<0.05). 당 주입율은 생리적 인슐린 농도에서 포도당 중합체군에서 감소하는 경향을 보였으나 최대인슐린 농도에서는 포도당 중합체군과 STZ 당뇨군에서 다같이 유의한 감소를 보였다(p<0.05). 간의 당생성율은 포도당 중합체군에서 생리적 및 최대인슐린 농도에서 다같이 감소하는 경향이었으며, 최대농도군에서는 유의하게 감소(p<0.05)하였다. STZ 당뇨군에서는 최대인슐린 농도에서 정상대조군 및 포도당 중합체군보다 증가하였다(p<0.05). 골격근과 간의 당원질 합성능은 포도당 중합체군이 정상 대조군과 차이가 없었으나 STZ 당뇨군에서는 감소하였다(p<0.05). 이상의 결과로 볼때 포도당 중합체투여로 유도한 고혈당 및 고인슐린증시 말초조직의 인슐린 저항성이 유발되었으나 soleus근과 간의 당원 합성은 장애가 없어서 STZ 당뇨군과 차이를 나타내었다.